The demonstration begins with a mission to install a backdoor virus into a CtOS database in a ramshackle industrial district in Chicago, Illinois.

Hinting at different non-playable character behaviours, level design director Falko Poiker explains that civilians in the poorer areas are less likely to react to Aiden's vigilante activity and call the police, giving him more license to break the law in pursuit of the bad guys.

Successfully completing the task unlocks full access to the district, allowing Aiden to hack into pretty much anything he wants, from traffic lights and bridges, to security cameras and gates.

The hacking system also gives players more options to complete objectives, removing the need to engage enemies directly, increasing Aiden's chances of survival.

It's a good thing too, because after tipping off the security guards to Aiden's presence during our first attempt, we were gunned down rather quickly by the goons.

Choosing to adopt a more stealthy approach, the first order of business is to access the location's security cameras, switching between vantage points by targeting cameras and holding the hack button. It really is that simple.

Scouting areas reveals the whereabouts of guards and their patrol routes, as well as making them visible to Aiden regardless of his position.

The best course of action is to then move to a quiet part of the compound, find a place to climb the fence using a parkour system that will feel familiar to Assassin's Creed fans, and then hide in cover.

It's now that you get a taste for the different options available to Aiden courtesy of his hacking abilities.

The game features a perfectly functional cover system, so you can simply duck and fire, or you can look for more entertaining ways to dispatch your enemies.

Keen to avoid confrontation, we activated a security door, which alerted the first guard and gave us an opening to sneak up and perform a one-button stealth kill. Other options include hacking into forklifts or cranes and dropping huge crates.

Installing the virus quickly and quietly, we moved onto a more affluent district, marking the route on our map and following the less-than-subtle road markings.

Like other open-world games such as Grand Theft Auto and Saints Row, Aiden can pick and choose from a wide selection of vehicles, each of which handles slightly differently.

The American muscle car, for example, is fast and powerful, feeling much heavier than a sports car, but isn't great for taking corners at high speeds.

Though we only tried out a couple of cars, the driving feels superior to games like Saints Row, and should complement the parkour system quite nicely.

Within the financial district we get an up close look at some of the benefits of hacking into the phones of regular civilians.

Although it seems at odds with Aiden's vigilantism, he is able to access people's bank codes, and make a withdrawal at a nearby ATM.

If you feel a little uneasy about stealing from innocent people, a quick click of the analogue button reveals more about their private lives, giving you all kinds of details about their job, income, and even how many pets they have.

Players can get a better taste for people's personalities by reading text messages, which on initial evidence, looks like it will inject a bit of humor and color into the gritty streets of Chicago.

Switching traffic lights to green is a nice way to get the cars moving ahead of you, all the while jamming traffic and slowing down pursuers. Our favorite way to lose the heat, however, is by raising a huge bridge and jumping it while it's halfway up.

We attempt to get our revenge on the hacker by infiltrating his game, but we're easily spotted when we panic and start to sprint as the download is nearing completion.

It's not the most engaging multiplayer mode, but it requires very little effort to get started, doesn't interfere with the main campaign, and could be a fun way to engage with friends.

Watch Dogs appears to borrow elements from Assassin's Creed, Far Cry and Splinter Cell, all the while adding some interesting twists of its own.

Based on early impressions, the hacking system is certainly the game's biggest strength, providing lots of inventive and additional ways to achieve objectives and waste time between missions.

Watch Dogs will be released on November 19 in North America and on November 22 in Europe for PC, PlayStation 3, Wii U and Xbox 360. Next-gen versions will be available at launch.